The field of this invention is flotation platforms, particularly of the inflatable variety, and method of making and using such flotation platforms. With still more particularity, the invention relates to a bifacial specie of inflatable life raft presenting a multitude of boarding stations by which an evacuee may enter the raft unassisted, and which also provide purchase for able-bodied evacuees aboard the platform to assist an injured or otherwise disabled person to board the raft.
Conventional inflatable life rafts are known which are bifacial. That is, the life raft when inflated and upon the surface of the sea presents substantially the same utility and serviceability with either side up. Further, a conventional bifacial life raft is known which presents a pair of boarding stations whereat evacuees may conveniently leave the sea and board the raft. For example, a life raft of such character is known according to U.S. Pat. No. 2,933,739, issued Apr. 26, 1960 to R. L. Miller, et al., wherein the life raft is composed essentially of a stacked pair of open-centered inflatable ellipses sandwiching a panel of fabric therebetween. The fabric panel defines a floor for the raft. The ellipses are rotated relative to one another and secured together so that the major axes of the ellipses are disposed perpendicularly to one another. The raft thus defines four boarding stations; a pair of which are useable with one face of the raft upward, and another separate pair of which are useable with the other reverse face of the raft upward. An inflatable step is provided at each boarding station.
Life raft constructed according to the teaching of Miller, et al., are believed to have many deficiencies. For example, the raft has only a pair of boarding stations which are usable at any one time. This feature of the Miller, et al., raft limits the rate at which the potential occupants may leave the sea and board the raft. After a ship wreck or airplane crash, there may be a multitude of persons in the sea, many of which may be injured and of short endurance. A delay in boarding an available life raft may mean death for injured or weakened persons who simply cannot struggle for life or tread water long enough while waiting for help or for their turn to board the raft. In the confusion and fear surrounding such tragedies, weakened or injured persons may simply slip beneath the waves and their loss go unnoticed at the time.
Further, a life raft according to the Miller, et al., teaching is believed to be comparatively bulky and heavy with a plurality of seams. Such is the case because the ellipses of the raft body are in fact defined by plurality of relatively short, straight tubular sections which are jointed to one another. Thus, each of the straight tubular sections must define a seam with each of its neighboring adjacent tubular sections. Such a multitude of seams adds both weight and bulkiness to the raft, and each seam presents the risk of a leak in the raft. The bulk and weight of a raft according to Miller, et al's teaching is increased still further by the inflatable step section provided at each of the four boarding stations. These step sections are four in number, although only two of the steps may be utilized at a time dependent upon which side of the raft is upward. Thus, the other two unused step sections are truly superflous bulk even though they are necessary with the life raft of Miller, et al.
Yet another shortcoming of the Miller, et al., life raft is believed to be its considerable difficulty of construction. That is, the life raft of Miller, et al., requires a plurality of straight tubular segments to be formed and joined with a plurality of seams therebetween. Thus, a large number of separate pieces of body fabric must be cut, fitted to one another, and joined by leak-proof seams to construct a life raft according to the conventional teaching. All in all, the life raft of Miller, et al., is believed to be inherently intensive of both labor and materials.
Further, a basic need has been recognized for a new type of life raft. This new specie of life raft is herein referred to as a flotation platform. The principal use envisioned for flotation platforms is aboard aircraft, even though they may also be used aboard other craft. Presently, aircraft which fly over bodies of water and more than 150 miles from shore are required to carry conventional life rafts and survival gear. However, aircraft which fly over water but never more than 150 miles from shore are required only to carry flotation assistance equipment, such as boyant seat cushions and inflatable life vests.
However, experience has shown that aircraft passengers placed into the cold sea by an aircraft wreck with only flotation assistance equipment have a very poor chance of survival because of exposure and hypothermia. Even though rescue equipment and assistance may require only a few minutes to reach the scene of the aircraft wreck or ditching, passenger survival rates may be very low. Thus, there has been recognized a need for a flotation platform which is relatively light in weight and low in deflated package size and bulk. Such a flotation platform may be carried aboard aircraft not designed to carry more than flotation assistance equipment, such a boyant seat cushions. Such a flotation platform need not provide facility for long-term occupancy. That is, water and food need not be provided, and extensive environmental sheltering for those aboard the platform need not be provided
Further, it is recognized that an optimized flotation platform will allow able-bodied evacuees to leave the sea and board the platform quickly. Additionally, such a platform should provide purchase for those able-bodied evacuees already aboard the platform to assist other evacuees in the sea, who may be suffering from injury or hypothermia, to board the platform. Still further, such a platform should include bifacial sea ballast structure which will assist in stabilizing the platform to increase occupant comfort and safety.